To prepare vinaigrette: Whisk vinegar, lemon juice, mustard, garlic, salt and pepper in a small bowl. Slowly whisk in oil. Stir in olives and parsley.
To prepare salad: Using a sharp knife, remove peel and white pith from oranges. Quarter the oranges; slice pieces crosswise.
Just before serving, combine lettuces, endive, fennel and the orange slices in a large bowl. Drizzle the vinaigrette over the salad and toss to coat well.