Do I have to stop play for lightning?

Bowls South Africa's domestic policy on law 33.1 says umpires are not responsible for calling players off during lightning or thunderstorm activity unless a player appeals to them.

When a game is interrupted, Bowls SA's Markers Guide for Beginners says the game resumes with the same score however long the break; an end that was started but not completed (including one not yet measured or decided when players left the green) is dead. If the game restarts the same day after bad weather, no extra trial ends are allowed; if it restarts on another day, normal trial ends are allowed.