I have always heard it pronounced (even by my SA at the BalNY store):
Ba-len-see-ah-gah, I have also read though that it can be pronounced with the soft c that sounds like our "th" sound - Ba-len-thi-ah-gah. I haven't actually heard anyone pronounce it that way though.
I did pronounce Bar lan char ga, like Italian way, even though I'm not Italian, lol. But my SA said Bar lan cee ar ga, so I guess I'll start pronounce like that. I'm also a newbie
This is an interesting thread. I've definitely heard variance on the c, but also on stress; I've heard SA's say: Bal-EN-ciaga, with extra stress on that second syllable.