Thank you, Lin!
I agree with Lin that it is far from an ideal location relative to the window. I understand that you have no choice about improving the light. That does not mean your Aralia will die, but it does mean that older, lower leaves will continue to gradually die because they are adapted to more light. However, new leaves will continue to merge and they will be better adapted to the reduced light. Over time, the stems will become more bare, leggy and taller with healthy new growth mostly at the tip ends of the stems. It should be okay, but it will look different than it does now. It will respond well to pruning.
I understand your frustration with watering instructions commonly available. Whenever I provide water interactions I want to first know how it is potted before I advise how deep into the soil it should dry before watering. There is no single answer for any one plant species. Very general watering instructions (water once per week or water when dry) are not at all helpful.
Your Aralia is potted in plastic so that tells me that it was not repotted by you and that the plastic will not dry out as quickly as terra cotta, as I thought it was originally. Your Aralia should be watered as soon as the surface of the soil feels just barely damp or slightly dry. That is as specific as I can be. My educated guess is that a thorough watering would suffice for about a week.
Caveat: These watering instructions are specific to your plant in its situation and cannot be applied to any other plants that you have.
