I played 'cello from grade school through high school, before taking up the bass. Recently I came across my box of 'cello music, including Mendelssohn's "Student Concerto" in D. Making allowances for my crummy technique and lack of stamina in the right hand, I struggled through the first movement, but was stumped at what to do about a couple sections of arpeggios that are playable on 'cello but not obviously so on bass.

Is there a generally recommended way to deal with a situation like this, other than to develop heroic technique? I am not preparing anything for performance, but am thinking that a Classical "phase" might just spice up my woodshedding. And I have a ready supply of 'cello music to work through before I have to spend any real money on charts.

Is there a generally recommended way to deal with a situation like this, other than to develop heroic technique?
Either change the Key of the piece or start tuning in 5ths.

Is there a generally recommended way to deal with a situation like this, other than to develop heroic technique?

No. Some things just can't be played. Change the music around so you can at least gain some satisfaction from playing the music. You aren't going to perform it and Mendelssohn is in no condition to complain.
There are many examples of transcriptions where passages are changed to be playable. Just have fun.

It really depends the arpeggios, but I'd go for the heroic technique

I vote for heroic technique.
I am working on Bach Cello Suite 1 Prelude myself. If, like me, you are using this as a technique builder, work through those arpeggios. I think its actually pretty cool to go from 3rd or 4th position to something up in the thumb postion - especially when you can get your intonation down and make it musicial. I go up and down that arpeggio to practice getting in and out of thumb position cleanly.

For some reason, I am really attracted to things that take your ego and throw it out the window. Like when I feel tough because I can play the head for a Charlie Parker tune, but I can't intonate a D Major scale with a bow in thumb position...:D Working through that hard stuff is what makes you better player in the long run.

PJ

I think it's ok to construct different solutions to suit your technique as you grow. Arpeggios can usually be revoiced without too much damage because they are usually used as accompaniment to the piano's (accompanist) occaisional melodic interludes or to usher in a new key, harmonic developement ,etc.. When your technique developes to where you feel confident, you might revert to the heroic version. For example, you can play some movements of the Bach suites in the lower positions as written, early on, then play them up an octave later as thumb position developes. Changing a chord inversion seems to be a small sin versus avoiding a piece that interests you and is begging to be plundered. Cello music needs to be raided regularly just for the effect. There are plenty of purists to preserve the composer's original intentions. I say, "Go for it".