Lakeside School can’t seem to stop offending racial sensibilities — particularly its own — when it invites speakers. Two years, the elite private school caused an uproar and embarrassed itself nationally by first inviting, then disinviting conservative author Dinesh D’Souza to speak. Now Lakeside, in the middle of a huge diversity push, is apologizing to the school community over a visitor from historically black Dillard University in Louisiana who repeatedly used the “n-word” as she read one of her poems aloud. See the e-mail from Upper School Director Than Healy here.