Cook ½ c elbow macaroni until tender, drain; refrigerate. Cook one 10 oz package frozen peas and carrots as label directs; drain, refrigerate. In bowl, combine ½ c mayonnaise, 1 Tbl lemon juice, 2 tsp horseradish, 1 tsp sugar, ½ tsp salt, 1/8 tsp pepper. Into it, fold cold cooked macaroni (1-1/4 c) and cold cooked peas and carrots. Refrigerate at once until time to serve.