  Quarkonium production in proton-nucleus collisions is a powerful tool to
disentangle cold nuclear matter effects. A model based on coherent energy loss
is able to explain the available quarkonium suppression data in a broad range
of rapidities, from fixed-target to collider energies, suggesting cold energy
loss to be the dominant effect in quarkonium suppression in p-A collisions.
This could be further tested in a high-energy fixed-target experiment using a
proton or nucleus beam. The nuclear modification factors of J/$\psi$ and
$\Upsilon$ as a function of rapidity are computed in p-A collisions at
$\sqrt{s}=114.6$ GeV, and in p-Pb and Pb-Pb collisions at $\sqrt{s}=72$ GeV.
These center-of-mass energies correspond to the collision on fixed-target
nuclei of 7 TeV protons and 2.76 TeV lead nuclei available at the LHC.
