lock handle tab - Anderson 400

I have an Anderson 400 casement series window. My daughter pulled off the lock handle and I guess the small metal piece on the lock mechanism that fits into the lock handle tab was broken off and is now missing. I suspect the metal piece is somewhere in her room but appears to be lost. Picture of the metal piece I am referring to is attached. I don't know what the piece is called but it fits into the lock handle tab. Not sure if I am able to buy just that metal piece or do I need to replace the entire lock mechanism. The lock mechanism is working fine - just the metal piece is missing. That metal piece might need to be welded on so I am not sure if it is easily replaceable or there is a substitute method to keep the lock handle on the lock mechanism. Thanks for your time.

I appreciate the quick response. That lock handle does not match. My dimensions appear to be 1 2/10 and 2 8/10.

Also I do not need a new handle. I have the lock handle. I am looking to replace the small metal piece located on the lock mechanism The missing metal piece fits into the tab on the handle. See photo.

Yes! That is the part. Thank you.