The semantic derivation from hanc hodie "this here day" to "also", "even" etc. does make no sense to me. The editor who added the etymology to wiki/anca and a many other languages, that share this idiom, wasn't very careful at least when formatting the entry (Edit: so that I totally missed the supposed connection to hanc hodie, but this does not change the question).
The reason I'm asking is, actually, Turkish ancak "only, best; but", which as a conjunction reminds more of anca; or Persian inja, anja "here, there". I sceptically doubt the Latin etymology, because what's broadly labled as Persian, that came to be identified with e.g. Ossetian, had been active west of the Black See. It would be nice to have that ruled out. But of course that has little to do with Latin or Greek, probably.
Since the sound change--which might be regular, that is the lack of h--is presented, one has to wonder two questions: First, whether vulgar Latin had this; Second; if it was ever there in the first place. It would be easier to follow the root in an-ja.
It's understandable that a word meaning here, there, then, etc could come to be used as conjunction, but that's a bit slim. Is it etymologically sound, as far as Latin or vulgar Latin is concerned?