While tests by NASA have indicated that the highest risk of lightning strike is at or near the tops of thunderstorms with low lightning strike rates, this is the least reported area of strikes by pilots, as the storm tops are so easy to avoid. Aircraft are highly protected against lightning, in any case, although damage does occur.
The worst risk is of fuel explosion - although there has never been a verified lightning induced fuel explosion on an aircraft using Jet A. (8/12/63 a Pan Am 707 was bought down by lightning strike, a Iranian Air Force 747 on 9/5/76, a US AIr Force C-130 in 1978 and an F-4 and KC-135 - however all were fuelled with, or partially fuelled with Jet B (JP-4) ).
It is far more probable that the "lightning" comment was a rushed conclusion from a non-expert from the "short circuit" ACARS message.
This would be the first fatal in-service accident for the A330 (an A330-300 was lost on a test flight.)