It’s not the end of the world but throughout the manual, the term elision is used incorrectly instead of liaison (it’s also used once in the 'Popovers in Dorico’ PDF). A liaison (the joining of two words) may involve an elision (the omission of sounds at the junction) but the two words can’t be used interchangeably. It’s not an unknown mistake in Britain but it is an error and can be annoying.
I’m sure the usual suspects will be tempted to try to start a fight over this but they might want to do a bit of research first.