When exporting from Lightroom, choose sRGB under Color space in the Export dialog.
I'm not familiar with Elements, but there should be an option to choose a color space there as well.
When I upload old photos I've taken (some years ago) the colors show true when uploaded to Adobe stock. When I tried to upload a photo I took just this week using a light box, editing in LR and then PSE9 the colors do not match what I'm seeing on my monitor. The colors are coming out muddy and muted. What's going on???????
Color Managed applications will produce the same preview from any tagged RGB color space. So I suspect one issue is, you’re not viewing the image in a color managed application. If upload, you mean the web, not all web browsers are color managed. Uploading sRGB alone doesn’t guarantee a match! Non ICC aware browsers do not know what sRGB is! See:
sRGB urban legend & myths Part 2
In this 17 minute video, I'll discuss some more sRGB misinformation and cover:
When to use sRGB and what to expect on the web and mobile devices
How sRGB doesn't insure a visual match without color management, how to check
The downsides of an all sRGB workflow
sRGB's color gamut vs. "professional" output devices
The future of sRGB and wide gamut display technology
Photo print labs that demand sRGB for output
High resolution: http://digitaldog.net/files/sRGBMythsPart2.mp4
Low resolution on YouTube: https://www.youtube.com/watch?v=WyvVUL1gWVs