The lookup search box does not recognize html
I can’t see why you would want to include HTML. So … er … why?
To provide a link to the detail of an item to open a new window so we do not loose the spot. Use it in every lookup.
You would need to create a separate URL field for the link.
I otherwise see that the URL you have in the HTML is to a record in SF. You can set as a lookup from this record to the “Event” record.
