FIRST OFF . . .

Lofti Mansouri, head of the Canadian Opera in Toronto, has been offered the job of general director of the San Francisco Opera, it was reported Wednesday. Mansouri, 58, has been among the leading candidates for the position since current director Terence A. McEwen last month announced plans to retire. “They have offered it, and I am considering it very seriously,” Mansouri told the Associated Press. He said he would decide by Friday. Ernest Fleischmann, executive director of the Los Angeles Philharmonic, was believed to have been the front-runner for the San Francisco post, but he withdrew his name from consideration on Tuesday. Mansouri has directed 31 productions for the San Francisco opera on a visiting basis since 1963.