It seems like people sometimes really just need time when confronted with poly. Be patient and chill and mention Lovely when appropriate without making a big deal of it and hopefully she'll come around when she's recovered from the shock.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.