In Romeo and Juliet, when does Friar Laurence promise Juliet that he will be there when she awakes?

In act
4, scene 1,visits 's cell and informs him thathas moved the wedding up in order to prepare a
hasty marriage. According to Paris, Lord Capulet believes that a wedding will lift 's spirits
and distract her mind from the death of her cousin. Shortly after Paris gives Friar Lawrence the
wedding news, Juliet enters the cell and requests to speak with Friar Lawrence. After Paris
leaves, Juliet desperately pleads for help and reveals that she is willing to commit suicide to
avoid marrying Paris. Seeing that Juliet is prepared to kill herself to avoid the upcoming
wedding, Friar Lawrence says that he might have a plan if Juliet is brave enough to go along
with it.

Friar Lawrence instructs Juliet to sleep by herself the next night
and hands her a vial, which contains a strong sleeping potion. He instructs Juliet to drink the
potion, which will put her into a deep sleep that replicates death. Friar Lawrence explains that
Juliet will remain in a deep sleep for forty-two hours and eventually wake up
refreshed.

While Juliet's body is being taken to the Capulet tomb and the
funeral is in session, Friar Lawrence will send word toin Mantua of their plan, and he will
rescue Juliet from the tomb before she wakes up. At the moment, Friar Lawrence's plan seems
foolproof, and Juliet agrees to go along with it.