Howard Jacobson is getting harder to ignore. The 72-year-old British writer has been publishing witty novels for more than three decades and attracting the kind of critical acclaim earned by stars like Peter Carey and Margaret Atwood. But he remains stubbornly obscure in the United States. “The Finkler Question,” his cerebral satire about anti-Semitism, won the 2010 Booker Prize (he’d been longlisted twice before), and his new novel, “J,” was on the shortlist for this year’s prize.