Because damage remains marked on creatures until the damage is removed as the turn ends, nonlethal damage dealt to creatures you control may become lethal if your life total drops below 7 life more than your starting life total or if Righteous Valkyrie leaves the battlefield that turn.

The amount of life you gain is equal to the Angel or Cleric's toughness as the triggered ability resolves. If the Angel or Cleric is no longer on the battlefield at that time, use its toughness from when it was last on the battlefield.