Q.Why Does My Orange Tree Not Fruit?
We’ve had one orange tree and one lemon tree for about ten years. The trees are kept in our porch through the coldest months. The lemon tree is fine and produces lots of fruit. However, the orange tree rarely gives any fruit. No buds, no flowers equals no fruit. We feed them both with a shop bought fertilizer; we replenish the top two inches of soil every year and every third year re-pot them using acidic soil. We prune them lightly each year. Otherwise, the two trees are very healthy. How can we encourage our orange tree to behave like its cousin the lemon tree and give us some fruit? Best regards Tim Rogerson trogerson@talk21.com

Certified GKH Gardening Expert
Here is an article that gives several reasons for an orange tree not fruiting.
https://www.gardeningknowhow.com/edible/fruits/oranges/no-fruit-on-orange-trees.htm
i'm wondering if pruning and pollination are a factor. Some orange tree varieties need a second tree for pollination.
Also, on the pruning, all you need to do is remove dead or damaged wood and open up the canopy every few years by removing some internal branches. When you say you "lightly" prune, I wonder if you are heading the tree, or cutting back branches by just a few inches. This can cause you to lose buds and flowers. Orange trees should not be headed back, but the whole branch removed, if needed.