In a large pot of boiling salted water, cook elbow macaroni according to package instructions. Meanwhile, in a medium bowl, combine mayonnaise, sour cream, cucumber, celery, dill, and lemon juice. Drain pasta, and rinse with cold water; add to bowl with mayonnaise mixture. Season with salt and pepper; toss to combine. Serve.
Refrigerate, covered, up to 1 day.