A query regarding prosody

While browsing through an old bookshop, I came across a volume that had the following note written inside (alas, I did not take a photograph—my apologies):

«Tempora labuntur; nobis inest cuncta momento nullo, restat in orbe diu.»

I think it's an elegiac couplet

«Tēmpora lābūntur; nōbīs īnēst cūnctūm mōmēntō nūllō, rēstat in ōrbe diū.»

…but there is something wrong with both the rhythm and the composition…