Hyphens dropped from words? Not in dictionaries over here anyway. Some word, yes. But new hyphenated ones keep on coming along.

What amazes me with this song is why so many people persist in singing the first line of the second verse the way Christina Rossetti wrote it, which with Holst's tune is virtually unsingable, no matter how people manage to struggle through it.

It works far better just as "Heaven cannot hold him", and means exactly the same. It's a lovely song, both words and tune, and deserves to be allowed to adjust itself so that the words fit the tune properly.