OK, here's a good one for you, and very improtant to me.

WHO, by welding or soldering, attaches the little ring to the front of
a fishing lure . . . the ring that attaches to the line.

NOT split rings.  I need a source to attach SOLID rings to a tiny
device that I am going to manufacture.  I expect the ring needs to be
about 3-4 mm in diameter.  I need the name of a company.

Can you do this?

There's an informative article on determining the best welding method
that you might find helpful

MacGregor Systems - looks to be the most comprehensive, but is UK based
http://www.macgregor-systems.co.uk/

http://www.moldmakingtechnology.com/articles/110403.html

Additionally these companies should be able to help you, I've listed
them in the order that looks most similar to attaching a ring to a
fishing lure

Rofin
www.rofin.com/english/applications/
laser-jewelry-jewellery-dental/micro-fine-welding.php

Microarcweld
http://www.microarcwelding.com/

Micro Weld Products Company - if you want to buy the equipment
www.micro-weld.com

Hope this is helpful