Initial Cast works yes - and should because you were in LOS. Afterwards it should *Not* be able to cast since LOS has been removed (for any further spell casting).
1.)
http://www.roath.demon.co.uk/Feign.htm
Bottom of Page.
"Use walls and line-of-sight to help split up multiple casters"
2.)
http://www.monkly-business.net/forum...hp/t-8933.html
Post from 2001: "Pulling Casters - Casters have a terrible habit of standing in one spot and casting at you over and over instead of coming to the party. This can be circumvented. Once a mob casts a spell it is not line of sight, IE, if you turn a corner the spell will still hit you. However, for most mobs the actually Begin casting a spell, you must generally be line of sight. So running around a corner or around an alcove will bring the mob running directly to a spot that's LOS with you."
Looking for more info. Those two alone though both state how it should work. Initial cast will always happen because you *were* within LOS. After you turn that corner though, and spell cast hits - if you are no longer in LOS it cannot cast. What I am trying to explain is that mobs are *STILL* casting within NON-LOS Parameters (Example: I am LOS around a corner, first spell cast hits, then second spell is being cast and I am still being hit while not within MOB Spell LOS).