I've just finished reading Matthew's gospel and in the very last chapter, came across this.

Matthew 28:6
He is not here: for he is risen, as he said. Come, see the place where the [u]Lord[/u] lay.

The word LORD leapt into my ears. Had Jesus been called Lord earlier in the book?

Yes, (a search revealed) but, never more appropriately, than there. The 53 other mentions of 'Lord' are justified beyond doubt, by just this one. :-D