From all that I have read it seems this is really an edc version of Arpege.
The year prior (1933) Lanvin had created its "eau" concentration, what in today's verbiage would equate to an edp. Concentration was a good 15-20% oils, which made their other eau formulations very close to the parfum itself, differing only in longevity, not in richness or depth.
So all their scents would have two concentrations, parfum and "eau." This particular scent, being an edc, could have simply been named "Lanvin Arpege Eau de Cologne," but they chose to eliminate the actual name of the scent. By 1934 only two of their scents had escaped being discontinued, Mon Peche (My Sin) and Arpege.