Hi Jennifer,
You have to talk to your lender. No one else can alter or change what your lender is intending to do, or not do.
It sounds like you are three months behind on the loan which is a common point where lenders will initiate foreclosure proceedings, the Thursday cutoff is most likely where they'll consider the loan as headed to foreclosure if a payment has not been made.
Sending the payment in after their cutoff date won't stop a foreclosure proceeding, the lender will return the payment and most likely require all past due payments in full.
Take the time to make contact with your lender and see if they'll agree to accepting your payment a week late.