Italian quello, questo

From: Andrew Jarrette
Message: 45209
Date: 2006-07-03

Speaking of Italian qu- as the group has been, I was wondering if anyone knew the origin of <qu-> in Italian <quello> "that", <questo> "this", presumably from Latin <ille, illud> and <iste, istud> with <qu> prefixed.  Does anyone know the origin of <qu-> in these Italian words?
 
Andrew