Alien Bob/Eric, thanks for the help. It didn't occur to me to add the “-cdrom” as well as the “-fda.” It works!
So, here is what I now have as an invocation line to install Win95 (having already created the <c.img> file, and with a Windows bootable floppy and the Win95 installation cdrom in the drives):
<qemu -fda /dev/fd0 -cdrom /dev/cdrom -k en-us -hda c.img -boot a -no-kqemu>
This gets me to an A: prompt, from which I can get to a C: prompt, which is the cd-rom, now working properly. After some false starts, I learned that these are the next steps (for my setup):
Return to A:
Run the MS-DOS command <fdisk>. I don't recall if it is automatically part of a Windows “emergency boot” disk or if I copied it onto the disk years ago, but it is very helpful to have. Go ahead and create a primary DOS partition, filling the whole “drive.” (I suppose one could create multiple DOS partitions, but I didn't try).
It says that you must reboot for this to take effect, so I did, via hard-reset (front panel button), as I was unable to get out via Ctrl-Alt-Fx to a tty screen. (This remains a problem even after installing Windows, when I “turn off the computer” from the Windows Start button. It goes to a blank screen and a locked-up computer.)
[Edited (again) to add: Silly me!!! I shouldn't "turn off the computer" from within Windows. I should simply use Ctrl-Alt-Fx while Windows is running. That goes out to the tty screen just fine. If I then want to "turn off" windows, just:
pgrep qemu
kill (whatever number pgrep returned for the process)
One of these days I'll figure out what's going on.

]
[and yet another Edit, the next day: Stupid Newbie Me finally figured out that Qemu is much happier when run within an X environment, and not out at the command prompt as I'd been doing it. I don't know about installation, but for regular operation of Windows, <startx> into your preferred window manager, open an Xterminal or equivalent, invoke Qemu, and now Windows can be shut down from the Windows "Start" button. Also you can go back and forth to other non-Windows application with ease.

]
Suitably re-booted, on to the next step:
<format c:>
I always get the jitters when I use this command, but it worked (without, for example, formatting my “real” drive, with my Linux system on it).
Now I can get a C: prompt, for which <dir> shows an empty disk, formatted and ready to go. And the cd-rom has magically moved to D:
So, from D:, run <setup.exe>.
By golly, it works! It only takes a few moments to get to the “Welcome to Windows Setup” screen. From there it proceeded normally.
In order to start Win95 from my Linux environment, I run
<qemu -hda c.img -fda /dev/fd0 -cdrom /dev/cdrom -k en-us -no-kqemu>
This boots from the <c.img> file, with access to the floppy drive and the cd-rom drive. My computer is old and slow, so the “-no-kqemu” is needed to make it work, and (as I learned) I still need the "-k en-us" in order for the keyboard to work.
Again, thanks for the help!