Senator Barack Obama and former President Bill Clinton plan to meet for lunch on Thursday at Mr. Clinton’s offices in Harlem, their first extended face-to-face encounter after more than a year of tense relations, aides said Sunday. The current plan is for Mr. Obama and Mr. Clinton to have lunch at the Clinton Foundation headquarters on West 125th Street in Harlem with one close aide each. There have been discussions about the men possibly then doing a walking tour of the neighborhood, but that has not been settled. Thursday is the seventh anniversary of the Sept. 11 terrorist attacks and...