Probably unnecessary. Both are benzodiazepines with a moderate (temazepam average 11 hours, Lorazepam average 15 hours) half life. Lorazepam is more potent, milligram for milligram, than temazepam. Combining the two would be like taking a larger dose, with consequently more main effects (sedation) and side effects. I don't think combining the two makes much sense.
Agree w Dr. Steele. Why take two benzodiazapines together? Use together can ^ risk for sedation, dizziness, v concentration & impairment in cognition/ judgment.