Luck and what it affects

[Olm]

So Luck cancels 50% of blows and magic hits.
What does that include?
Blows are rather clear.
Direct magic damage also, AOE damage is also covered.
But what about poison for example? Can it only prevent getting poisoned, or does it also prevent the subsequent poison damage?
And what about unresistable effects, like from Song of Power or Life for a Life? Does it work there?
And what with globals like Seeking Arrow or Mind Hunt or Flames from the Sky?