Children of Korlis and losing life

[Guli]

When you pay life for cards like Force of Will, Dark Confidant, Necropotence, Sylvan library, Fetching... can this life be gained back with Children of Korlis in that turn later on?

Or is it only the life loss from damage that was dealt by creatures and burn spells that can be gained back?

[Roxas]

Children of Korlis |Creature -- Human Rebel Cleric| 1/1. Sacrifice Children of Korlis: You gain life equal to the life you've lost this turn. (Damage causes loss of life.) TSP,PLCTD-C [Vin Leg Ext Std legal.]

You can use it to gain back any life lost over the course of the turn regardless of the source, including all of those things you listed.