I have just been given a Chinese Elm, It looks to the un educated eye to
have been cared for intitialy but the leaves are turning yellow and I am
concerned that there is something wrong.

Where are you keeping it? It should be outdoors for the summer, but in the
shade initially. The Sunset Bonsai book is easily obtainable & good for
beginners.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)