This prefixed derivative of sivre is probably a direct calque of the Latin verb sub + sequi, which it is translating in this sole attestation.
v.a.
1to follow, be with:
(
s.xii1; MS: 1155-60
) Mais e benignited e misericorde suzsiwerad (var.
(P: s.xii4/4) suzsiwerat
) mei tuz les jurz de ma vie (Latin: Sed et benignitas et misericordia subsequetur me omnibus diebus vitae meae)36.XXII.6
[suzsivre] (s.xii1)