Several effects state they occur "for X number of turns" or last until the end of turn. Rarely, will two effects will seem to happen at exactly the same time (these will actually have a resolution order) -- It's much more common for one effect to happen before the other. In some cases, the order of effects (order of resolution) has a significant effect on the final outcome; for example, the spell Impervious states it lasts 2 turns while Hive takes effect at the end of your turn.
Usually (but not always), this happens in the order the effects took place (if Impervious were used before Hive was deployed, then Impervious would be removed before Hive took effect).
However, it's important to note that the game computes all end-of-turn damage, loss-of-Life, and healing, before it checks to see if the champion's HP is 0 or below. (These effects are thought to happen "at the same time".)