Defending champion Gregory Havret, Steven OHara, Wade Orsmby and Ake Nilsson were a shot back.
Lawrie, who is working with Padraig Harringtons coach Bob Torrance, had an eagle-3 from 45 feet at the ninth hole.
Lawrie said he doesnt mind playing in bad weather.
With the rain, the last five or six holes were very tough, he said. I never really struggled except at the 18th, where I hooked my second shot.
He still made par.
Colin Montgomerie had an opening 76 for the second straight week, although hes just 4 over par. Last week, he missed the cut at the Dutch Open.
I didnt play well, obviously. Ive been playing badly all year and it just continues, said Montgomerie, who had a double-bogey on the 13th and seventh holes after starting at the 10th.