From the "O" Antiphons: the promise of tomorrow
The first letters of the titles, from last to first, appear to form a Latin acrostic, 'Ero cras', meaning 'Tomorrow, I will be [there]', mirroring the theme of the antiphons. This is formed from the first letter of each title – E mmanuel, R ex, O riens, C lavis, R adix, A donai, S apientia.
Indeed, in a special way, HE will be there tomorrow. And he is always with us!