Is it True That I’ll Lose Coverage At 70 – 75?

No one loses coverage, for any reason, other than non-payment or fraud. Coverage is guarantee issue, and the ratio of what someone can be charged based on age is 3 to 1.

All of this can be found in the PPACA itself. For the sake of making life easy, you can find this information in Title I. You can see our summary of the PPACA here and since these provisions happen to be right in a row and an easy copy and paste, here they are:

• Sec. 2701. Fair health insurance premiums. Establishes that premiums in the individual and small group markets may vary only by family structure, geography, the actuarial value of the benefit, age (limited to a ratio of 3 to 1), and tobacco use (limited to a ratio of 1.5 to 1).
• Sec. 2702. Guaranteed availability of coverage. Each health insurance issuer must accept every employer and individual in the State that applies for coverage, permitting annual and special open enrollment periods for those with qualifying lifetime events.
• Sec. 2703. Guaranteed renewability of coverage. Requires guaranteed renewability of coverage regardless of health status, utilization of health services or any other related factor.

I think you hit the nail on the head, misinformation by the anti-ObamaCare folks. Here is the "lose coverage at 75 myth" busted on another website as well.