I don't feel that the altitude will create any problems as the Anthurium is found in fairly high places, certainly higher than your flat. Just keep looking after your plant as you have been, remove the "flower" stem, as it dies back, from just above the plant and in time you will find new shoots emerging on which the tips will unfurl presenting you with some new "willies on a plate".Don't be disappointed if they are not as showy as the originals for unless you can replicate the conditions in which your plant was grown they will be appreciably smaller.