Combine beef, lemon juice, Worcestershire, salt and pepper in heavy-duty food-storage bag; seal. Refrigerate for 2 hours.
Heat 1 tablespoon oil in large skillet over medium-high heat. Add onion; sauté until golden brown, 3 to 5 minutes. Add mushrooms; sauté until softened, 3 to 5 minutes. Remove to bowl; keep warm.
Increase heat to high; heat remaining oil in same skillet. Add beef; sauté 2 minutes. Reduce heat to low; stir in onions and mushrooms.
Whisk broth, flour and tomato paste in bowl until smooth. Stir into skillet. Cook, stirring, until slightly thickened and bubbly, 2 minutes.
Stir in sour cream; don't boil. Serve over noodles; top with olives.