Cut apple into quarters. Remove the core and seeds. Cut into thin slices and place in the bowl with the orange juice. Stir to insure slices are all covered. Place in the refrigerator until use.
Wash and spin dry lettuce leaves. Cut or tear them into bite sized pieces. Place them in a large mixing bowl.
Chop celery stalk finely and place in the mixing bowl.
Cut grapes in half and place in the mixing bowl.
Place all apples except for four slices in the mixing bowl.
Add the walnuts and vegan mayonaisse to the mixing bowl and gently toss until salad is just combined.
Divide salad between four plates and top with apple slices and freshly cracked pepper. Serve immediately.