(a)  The mortgage deed and the rights established therein, shall, to the extent of the loans secured thereby, and interest, taxes, insurance premiums and other obligations as secured thereby, have full priority over all mortgages, liens and encumbrances which have not been recorded prior to the recording of the mortgage deed except as otherwise hereinafter provided.

(b)  If, after the recording of the mortgage deed, any writ of attachment attaching the real estate mortgaged under the mortgage deed or any execution against the real estate or any notice of lis pendens affecting the real estate or any subsequent mortgage or lien against such real estate be recorded in the records of the city or town, any optional or nonobligatory advances secured by the mortgage deed which are made by the mortgagee after receipt of written notice by the mortgagee at the address provided for such purpose in the mortgage deed, shall not have priority over the lien of the writ of attachment, execution, lis pendens or subsequent mortgage or lien, except that any obligatory advances which the mortgagee agreed to make by agreement entered into with mortgagor prior to receipt of written notice and any taxes, insurance premiums and obligations of the mortgagor as the mortgagee has agreed, or which the mortgagor has given the mortgagee the right, to pay in connection with the mortgage deed, shall continue to have priority over the writ of attachment, execution, lis pendens, or subsequent mortgage or lien. For the purposes of this chapter, an “obligator advance” is defined as any advance or principal which the mortgagee is obligated to make, absent the occurrence of an event of default under the mortgage or any corresponding loan agreement or notes, on or before a specified date or time or upon application therefor by the mortgagor or other obligor whose indebtedness is secured by the mortgage.