Info from brushwood nursery
Pruning- Thunbergia mysorensis may not need much pruning in its first year or two. Cut only to guide the plant to the form you want it to take. Always cut just above a bud to avoid leaving a long section of dead stem, which will attract disease. In future years prune and direct stems during the winter or early spring while the leaves are off so that you can see the structure of the plant. Remember that the plant will branch at the point of the cut, so prune low for a fuller appearance or remove all but two or three stems to train long over an arch or arbor. Always remove diseased or dead stems as you see them, whatever the season.