With most bulbs it is obvious, but with some it is more difficult to tell. Mine had what looked like small protrusions on the side that pointed the direction for up. Usually the top has a dormant spike, or there are side bumps, that will produce shoots. For me those gave the best clue to proper orientation. The top will generally be a bit more pointed, the base a little flatter. Maybe if looking closely some remains of root hairs may be seen around a ring kind of area on the bottom. As am calling this from memory, the info could be a bit suspect.
Sorry I can't be of more help on this one. Perhaps and elephant ear expert will chime in.
Eclectic gardening style, drawing from 45 years of interest and experience. Mostly plant in raised beds and containers primarily using intensive gardening techniques.