Chinese Elm green leaves with black spot

I have a ten year old Chinese Elm I inherited. Some leaves (mostly on same branch) have a small black spot on them. Is this the process of shedding leaves or the start of the black spot fungus. Thanks so much in advance for your help, it's greatly appreciated!

Sonds like black spot to me. All Elms can be troubled with this fungus and is easily treated with a diluted Lime Sulphur spray. 1 part LS to 30 parts water should do the trick. Remove and trash any infected or fallen leaves.

Is the lime sulfur (powder)available at nurseries? I have heard of Neem oil for this also. Is this a treatment also? Thanks for any advice

Lime sulfur is sold as a liquid. You dilute it at something like 40:1 as a spray for the disease. I haven't seen it in smaller than a pint bottle -- which is a lifetime supply for a bonsaiest.

When you remove the leaves, remove them completely from the area; the garbage pail is good. And stop watering in a way that gets water on the leaves.

Is there an echo in here.
You may find some bonsai nurseries split a big bottle up but its not that expensive anyway. Some people make their own but I would advocate cooking it outside if you value your life. Its quite smelly.