If one loses line of effect when sustaining a power, then the effect is deactivated until LOE is re-established, correct? Or is it the case, that if you LOE when sustaing a power, then the effect is no more, period?
At the end of your turn, if you don't have line of sight to your conjuration, then it ends. So if you don't even have line of effect, then it would also end in that case.
