Sec. 7.04. DURATION OF SPOUSE'S BENEFIT. The benefit payable to a surviving spouse is payable throughout the surviving spouse's remaining lifetime. A surviving spouse whose benefit was terminated under this section as it existed before September 1, 1997, is entitled to receive a benefit beginning on the date the surviving spouse files an application for resumption of benefits with the board of trustees, but is not entitled to receive a benefit for the period in which the benefit was terminated under the former law.