Flipping this around, is there a good reason to deviate from convention? In general OSM prefers names in full: https://wiki.openstreetmap.org/wiki/Abbreviations

I personally see no good reason to abbreviate Québec; OSM data does not need to accommodate automated envelope readers, is not bound by space limitations on a paper form.  Also non-abbreviated names are unambiguous to people unfamiliar with the area.
