What is the best approach for installing a handrail on steps leading to a porch?

For a situation involving an elderly person, function and stability are way more important than matching the concrete color perfectly. You should lean toward a solid wood or composite railing system rather than a simple post and rail design, expecially since the slope is steep. A solid rail gives them a much more substantial surface to grab onto without worrying about their hand slipping through gaps, which is critical when they are ascending a challenging grade. In terms of the setup, you absolutely want that rail to run the entire length of the steps. Most accessibility guidelines require the handrail to be continuous for the full flight of stairs. Starting the rail at the very bottom is a good practice because it allows someone who might need support entering the steps to maintain a continuous grasp from the ground level. When thinking about length beyond the steps, the standard requirement is usually that the rail must extend past the very first and the very last step. This extension is necessary so the person using the stairs has a solid point of contact even when they are just about to step onto the platform or step off the ground. It takes that little extra bit of material to meet code and provide real safety.

If you are worried about the wood looking too stark against the new concrete, you can use stain selection to help. Choose a tone that complements the natural color of the aggregate in the concrete, rather than trying to perfectly match the gray. Using brackets that are a similar color to the wood itself helps hide the mounting hardware and makes the whole thing look more unified.

I agree about going solid, especially with a steep grade. A simple post and rail just doesn't feel stable enough when you're trying to help someone ascend. Regarding the height, it really makes a difference in leverage and comfort. I always install my rails at 34 inches above the stair nosings, minimum, to give people that proper grip. I've found that any lower and they start dragging thier shoulders. Also, make sure whatever posts you use are deeply set into the concrete, not just bolted on the surface.

I'm a little torn on the mounting method since my project is for a side patio, not the main house entry. I genrally use heavy L-brackets for my small projects, but I don't want to mess up the finished concrete with improper hardware. What kind of anchors or fasteners do people usually swear by when bolting rails into poured concrete to make sure they realy won't slip? I've heard some people use tapcons or specialized masonry anchors, but I just want to make sure I don'm not under-engineering it.

I'm worried that if the posts shift even a tiny bit, the whole setup becomes useless for someone needing real support.

I gotta push back a bit on the idea that you absolutely have to start the rail right at the bottom of the steps. While I get the theory of continuous support, I think that's a huge overdesign for most situations. If the grade isn't that extreme, starting the rail once you hit the first riser is plenty for safety. Requiring it to go all the way to the ground level seems more like an absolute code requirement than practical advice for a residential backyard setup. Most folks just start where the steps begin.

Update: decided solid rail is the way to go, you all talked me into it. One thing still hanging me up though, mounting hardware. Someone mentioned heavy L-brackets but I've got cured concrete now and I'm guessing standard screws won't cut it. Do I need to set anchors in with epoxy or is there a simpler option? Also still unsure if the rail should extend past the top step.