Yes. Actually, the best time to take Olanzapine and Lorazepam is at bedtime because they are sedating. Some people take the Olanzapine after supper and the Lorazepam right at bedtime because it is faster acting. If the Olanzapine by itself controls your anxiety and puts you to sleep, you may skip the Ativan (lorazepam) all together and just take it as needed for breakthrough anxiety.
Check with doctor. who is treating you, before adding any over the counter medication or dietary supplement. The doctor who is treating you and prescribing for you should be the one you ask.