Greek Kappas Can Also Stand In For Latin Qu's

[1] Ἐγένετο δὲ ἐν ταῖς ἡμέραις ἐκείναις ἐξῆλθεν δόγμα παρὰ Καίσαρος Αὐγούστου  

ἀπογράφεσθαι πᾶσαν τὴν οἰκουμένην:             

           And it happened in those days that there came out a decree from Caesar Augustus that the whole world be enrolled; 

[2] αὕτη ἀπογραφὴ πρώτη ἐγένετο ἡγεμονεύοντος τῆς Συρίας Κυρηνίου:              

            This first enrollment occurred while Quirinius was governing Syria.

                                      -ΚΑΤΑ ΛΟΥΚΑΝ - The Gospel of Luke 2.1-2. Trans. is my own

When reading an ancient text, it is often helpful to keep in mind that what one is reading has probably been a good deal influenced by what a scribe has heard. Elisions and other orthographic alterations often occur in texts which were dictated by an author to a scribe, for the scribe would merely record what the master spoke aloud, elisions and all.
This process of dictation becomes even more woolly when one begins translating between languages; for example, what would an ancient Greek speaker hear when a Roman said the name "Augustus" to him? How would the Greek accent that name? Would he pay much attention to how the Roman said it, or would his natural Hellenic tendencies take over and would he pronounce it as a Greek speaker would (cf. Catullus LXXXIV)? By comparison, we know what the Greeks did with proper nouns like Jesus and John: the Hebrew יֵשׁוּעַ "Yeshua" was transliterated as Ἰησοῦς ("Iesous") by the Greeks; and John originates from the Hebrew יוֹחָנָן "Yokhanan", which was taken by Greeks as Ἰωάννης ("Ioannes"), and then by the Romans as "Iohannes/Ioannes" to be later Anglicized to "John". 
Roman names like "Valerius" gave the Greeks some additional trouble, as the V, making a w sound (the digamma having dropped out of Greek centuries earlier) was transliterated by ou: Οὐαλέριος.
So, wanting some of the sounds common in Hebrew (e.g. "sh", "v/w"), the Greeks did what they could with what they had.
Armed with this knowledge, we can clearly see from the above verses how Luke transliterated "Augustus": "Αὐγούστου" is the Genitive of Αὔγουστος - no problems there. 
But what about a name like Κυρήνιος? The transliteration of this name would be Kurenios, which would be further Latinized to Cyrenius - but could the name also be transliterated as "Quirinius", as Classical Greek lacks the "qu" sound?

What evidence may we gather which proves how scribes of the day grappled with their own spelling conventions in transliterating the Greek kappa to the Latin q and vice versa? In the Regula Sancti Benedicti ("The Rule of St. Benedict"), a guide written in the early 6th century A.D. for the formation and maintenance Western Christian monastic communities, St. Benedict tells when the Christian liturgical prayer, Kyrie eleison ("Lord, Have Mercy") is to be said:

"Post hos, lectio Apostoli sequatur ex corde recitanda, et versus, et supplicatio litaniæ, id est Quirie eleison. 

"After these [prayers], a reading of the Apostle may follow, which is to be recited by heart, and verses, and the petition of litany -- that is, the Kyrie eleison."                       

                                                                    -Regula Sancti Benedict IX. Trans. is my own.

This petition is, of course, Greek, and is written properly as Κύριε, ελέησον, and is usually transliterated as "Kyrie, eleison". This is not, however, how St. Benedict (or, at least, his scribe) has written the prayer: the scriptor has exchanged the Greek kappa in Κύριε with q- to give us "Quirie eleison".
And lest it be pointed out how dubious and misguided it is to entirely trust an Internet source, let us turn to a handful of manuscripts (which are numbered) of the same text which were written in the various centuries spanning from Late Antiquity to the Middle Ages and focus our attention on how the Kyrie is spelled with both k's and q's (and even c's!):

1.

St. Gallen, Stiftsbibliothek Cod. Sang. 914, dated first third of the 9th century A.D.

2.

Oxford, Corpus Christi College, MS.197, fol. 32v, dated late 10th century A.D.

3.

Hatton 48, Canterbury, c. 8th century A.D.

Other instances of the Kyrie in the Regula and its manuscripts follow suit (sometimes the same manuscript will exhibit different spellings!). Since the variance of spellings between k's and q's (and even c's!) in the many centuries following the diminishing of the Roman empire in the West, it is reasonable to assume that such differences and confusions were most likely commonplace throughout the entire intercourse of Greek and Latin.