Talk:Cassiopeia/@comment-24055932-20150605151920/@comment-4636093-20150606085420

Actually it's kinda odd. It checks both at the start of cast and on impact, if the target was poisoned at any point in between those then the cooldown is lowered.

So Cass can both cast Q, then E before it detonates, then when the E lands on the now poisoned target the cooldown is lowered. And also if she Es someone and the poison wears off before it lands the cooldown is also lowered.