Of Janine Jansen, the conductor Paavo Järvi has said, “She plays like she is. She’s a person of genuine warmth, genuine feeling, genuine expression. There’s nothing fake, nothing manufactured or prepared. The expression feels like it’s happening now and it’s honest. It’s like a child.” To complement Jansen’s interpretation of Sibelius’s lone essay in the concerto genre, Sakari Oramo is dusting off a far-less-known Nordic beauty: the Danish composer Rued Langgaard’s rapturous Symphony No. 1, “Cliffside Pastoral,” introduced by this very orchestra in 1913. —Matthew Gurewitsch