Well, I opened thread to provide that exact answer, but not needed now...
Strangely, I'm confronted with a need for an Events that fires on game entry after the engine creates Autosave_Initial_0000 BC-4000.Civ5GameSave. By testing, Events.LoadScreenClose fires right before that. (No big deal though. I can build a one-time listener from unit dirty or something like that.)