Veteran comic Jerry Lewis, 74, announced yesterday that he has signed a 20-year contract with the Orleans hotel-casino in Las Vegas, “with the provision (that) when I’m 94 I can work with a walker,” he joked at a news conference. The Orleans showroom, with only 1,000 seats, is one of the gambling city’s smaller venues, which Lewis says will make it better for him to connect with fans. He would not disclose financial terms of his deal, other than to say of hotel boss Michael Gaughan, “If I croak . . . he still has to pay me.”