Can You Say ‘Baruch Hamavdil Bein Kodesh Lechol’ in the Bathroom?

Yes, it is said in the name of Rabbi Yosef Shalom Elyashiv.

Perhaps it’s better to say “Shavua Tov” instead. Are blessings using a nickname (חנון ורחום הגדול הגבור והנורא הנאמן קנא וחזק וכיוצא) also allowed de jure?