Students can continue to practice finding elapsed time daily with a new problem, new time, new type of problem, etc.
Elapsed time is a difficult skill for many students solely because there are SO MANY kinds of problems that require them to find elapsed time (looking for the end time, working backward to find the start time, finding the amount of time that has passed, etc.)
I have my students do this each morning/beginning of the math block depending on our school wide schedule for the following weeks after our unit on time. I give them a different start time/end time/ or amount of elapsed time each day. They can use any of the strategies we have learned to solve for what is missing.
Doing this practice 4 times a week gives many students the receptive practice of identifying what they know and what they need to find, and how to find it. This allows them the practice to gain the confidence of knowing what to do in real life situations.
Could be given where you write the time before copying and given as weekly homework after skills have been taught.