Of course the correct answer, long term, is to develop the ability to sit comfortably for long periods in lotus. Which, however, starts with developing the ability to sit very uncomfortably for very short perods in lotus. And takes years.

My daily practice of pranayama and meditation are back on the floor, rather than in my comfortable Norweigan balans chair, except when I do them at work during lunch hour. Twenty minutes in easy pose is close to all my legs can take, but it's important to start down the road, even though I can't do lotus now. I sense that it will help increase my strength and flexibility. I still need to sit on blocks so that my knees are at least at the same height as my hips.

I got away from doing my practice on the floor when I injured my lower back and long stretches in a cross-legged seated pose tended to put more stress on my lumbar area. But now my back is no longer a primary concern.