See the results of this poll: Which Pr. of Isolde?
Respondents: 58 (This poll is closed)
- EE-SAUL-DUH : 10 (17%)
- EE-SOLD : 39 (67%)
- Other: 9 (16%)
I pronounce it more like ISS-OLD… but I might be wrong ^^.
Since I think it comes from the original spelling of [name_f]Yseult[/name_f], I try to say it as close to that as possible, which on your list is ee-sold. Other ways I might think to pronounce it are iss-old and ice-old, but ee-sold definitely sounds better 
BTW, I think ee-saul-duh just sounds like ee-sold with an accent.
I don’t know about correct but I say it most like EE-ZOLD
I say ee-sol-duh (sort of a mesh between the two you offered).
I pronounce it as bibliophile does.
I say iss-old-uh.
It’s three syllables. I say ee-ZOL-deh.
Yeah, I say it most like this I think.
I say ih-zold, but voted EE-sold because they’re close enough.
I’m pretty sure the correct pronounciation is with three syllables, but I prefer it with two 
Ditto, but sometimes I give it a little “eh” sound at the end.
I say it ee-zold-eh because that’s the way my professors say it and it’s the only way I’ve ever heard it.