Helicopters are much more problematic with respect to lightning than fixed-wing. You don't need to be grounded, just have an electrical charge opposite to that of the bolt. And if you don't think helicopters build up an electrical charge, just grab a cargo hook while one is hovering! The strike can cause much more catastrophic damage to a helicopter, because of all the moving parts. If the strike exits a main rotor blade, it can cause balance problems, perhaps major. I've seen the results of strikes going through the transmission, which left the bearings badly damaged. Very scary stuff.
And the fatal S76 crash in the North Sea not so long ago resulted, at least in part, from a previous strike on a main rotor blade. Anyone who believes that an aircraft can't be struck by lightning is very ignorant.
As for the R22, who knows. Doing hover work at 20' or so isn't usually a problem from a visibility standpoint, but I think I would have waited for better weather if there was any choice - and there is almost always a choice.