śrī-śuka uvāca
athaikadā dvāravatyāḿ
vasato rāma-kṛṣṇayoḥ
sūryoparāgaḥ su-mahān
āsīt kalpa-kṣaye yathā
sri-sukah uvaca -- Sukadeva Gosvami said; atha -- then; ekada -- on one occasion; dvaravatyam -- in Dvaraka; vasatoh -- while They were living; rama-krishnayoh -- Balarama and Krishna; surya -- of the sun; uparagah -- an eclipse; su-mahan -- very great; asit -- there was; kalpa -- of Lord Brahma's day; kshaye -- at the end; yatha -- as if.
As Srila Visvanatha Cakravarti Thakura points out, the words atha and ekada are commonly used in Sanskrit literature to introduce a new topic. Here they especially indicate that the reunion of the Yadus and Vrishnis at Kurukshetra is being narrated out of chronological sequence.
Srila Sanatana Gosvami explains in his Vaishnava-toshani commentary that the events of this eighty-second chapter occur after Lord Baladeva's visit to Vraja (Chapter 65) and before Maharaja Yudhishthira's Rajasuya sacrifice (Chapter 74). This must be so, the acarya reasons, since during the eclipse at Kurukshetra all the Kurus, including Dhritarashtra, Yudhishthira, Bhishma and Drona, met in friendship and happily shared the company of Sri Krishna. At the Rajasuya-yajna, on the other hand, Duryodhana's jealousy against the Pandavas became irrevocably inflamed. Soon after this, Duryodhana challenged Yudhishthira and his brothers to the gambling match, in which he cheated them of their kingdom and exiled them to the forest. Right after the Pandavas' return from exile, the great Battle of Kurukshetra took place, during which Bhishma and Drona were killed. So it is not logically possible for the solar eclipse at Kurukshetra to have happened after the Rajasuya sacrifice.