Like so many things in botany I think it gets complicated. Organisms die when the soil drys and this probably leads to a surge of available N when moisture returns- sure seems like it when we get rain after drought here. Accumulated dust gets rinsed off the leaves, undoubtedly some percentage of it harmful. Irrigation water is often alkaline, leaves get an immediate drink, and so on.
From what I’ve experienced, East Coast nurseries produce bigger trees after a dry season, which I’ve always assumed was the result of ample sun and well irrigated soil.
We all know that it takes much less N to get plant response when it is applied in foliar form, so I can see how a thunder storm wouldn’t have to release that much N to get a response from the grateful plants.
So I hope that clarified EVERYTHING.