When Sower of Temptation's enters-the-battlefield ability resolves, if Sower of Temptation has already left the battlefield, that ability will do nothing (its effect won't "start and immediately stop again"), so that control of the targeted creature won't change (C.R. 611.2b). See also this thread.
While the trigger of Sower is on the stack, my opponent plays a Lightning Bolt on the Sower.
Do I get control of the opposing creature and give it back immediatly, giving the creature summoning sickness?
Informal warning issued for absence of card tags, tags added. Please check your private messages. -MadMage