hello Lucycharm,
I haven't used the Lidoderm patches but I've read the tips made by others that do use them.
seems like there were just some posts last week on a thread - I'll try to find it and post the link here for you.

Some cut them in half or in a shape that will fit better

make sure skin is free of oils or lotions - it might have been mentioned to clean the skin with alcohol ??- so they stick better

if they still don't stick use a medical tape to secure it- some tape is better than others.

Elbow pain-
yes it goes with TOS quite often but it could also be ulnar nerve/cubital tunnel or both TOS & cubital tunnel. {called a double crush - because of 2 places being affected separately}.

I had elbow pain mostly due to the muscle spasms in my neck, arm and shoulder areas - besides the tension and pulling, the spasms were affecting my ulnar nerve - when we got the spasms under control the elbow pain went away for me.
My elbows were very sensitive to pressure and had sore spots around the joint - no arthritis at all though- they checked for that.
some swelling and weakness, soreness when lifting a milk jug- that sort of thing, and just a dull ache the rest of the time.

trigger points can also cause referred pain like this chart shows-
you don't need the tool - just a tennis ball , or any firm ball on the floor or against a wall or a friend willing to try it for you.
this explains it a bit -
http://www.pressurepointer.com/Users1.htm
and the clickable chart-
http://www.pressurepointer.com/pain_reference_chart.htm