Film fans appreciate “The Lion in Winter,” but a select group of them in Southern California also have a thing for the Arthur Lyons in spring. That is, the Arthur Lyons Film Noir Festival , which takes place each May in Palm Springs. The four-day fest, set to run Thursday night through Sunday afternoon, offers a hefty dose of filmic darkness to the sun-soaked locals but also a good excuse for Los Angeles cineastes to take a drive out for a long weekend, with plenty of hard- or impossible-to-see rarities on tap as a reward. The 2026 edition of the festival (named after the late crime writer who started it) kicks off Thursday with the digital premiere of a Film Noir Foundation-led restoration of “Slightly Scarlet,” the rare legitimate film noir that is in ‘Scope (not Cinemascope, but a close enough facsimile thereof).…