Season lamb with kosher salt and freshly ground black pepper. In a large casserole lightly coated with oil over high heat, brown lamb until nicely caramelized, about 6-8 minutes. Remove lamb to a plate. In that same casserole, add onions, carrots and celery and season; sauté until softened, about 3 minutes. Deglaze with red wine and reduce by 50%. Add orange quarters, soy sauce and brown sugar. Stir to combine and taste liquid; season if necessary. Add lamb shanks, bring liquid to a boil, cover and reduce heat to low. Simmer for about 3-4 hours or until meat is falling off bone. In a large saute pan over medium-high heat, combine 1/2 cup braising liquid, lemon juice, orzo and scallions. Toss to combine and heat through. Mound orzo on platter and top with lamb shanks, spoon braising liquid over and top with Clementine Marmalade.