Banksy, the ever-elusive artist well-known for his hidden identity, may be forced to reveal his name after art collectors sued him for refusing to authenticate a print. Nicky Katz and Ray Howse sued Banksy’s company, Pest Control, for what they say is a refusal to authenticate their print of “Monkey Queen,” which they acquired for around $38,500. If the lawsuit makes it to court, the artist — who’s only revealed his first name, Robbie — might have to give up his full identity. The print, which features a Queen Elizabeth lookalike as a monkey with a crown and jewels, only...