Display only Future Events

I’m building with Oxygen to create a calendar and using a Repeater to populate those events. I’m using the following WP Query to display the events:

post_type=event&orderby=meta_value&meta_key=_event_start_date&order=asc&no_found_rows=true

Where I’m stuck now is with how to query only Future Events with the Repeater as opposed to displaying everything at once including past events.

Any suggestions? Thanks!