1. Heat the olive oil in a large pot or Dutch oven over medium heat. Add the chopped onion, diced carrots, and diced celery. Cook, stirring occasionally, for 5-7 minutes until the vegetables begin to soften. They should look slightly translucent and tender, but not browned.

2. Stir in the minced garlic and cook for another minute until fragrant. Be careful not to burn the garlic. Pour in the chicken broth, scraping up any browned bits from the bottom of the pot. Bring the mixture to a gentle boil.

3. Once the broth is boiling, add the orzo pasta. Reduce the heat to medium-low and simmer for 8-10 minutes, or according to package directions, until the orzo is al dente (tender but still firm to the bite). Stir occasionally to prevent the pasta from sticking to the bottom of the pot.

4. Stir in the shredded or diced cooked chicken and the fresh lemon juice. Continue to simmer for another 2-3 minutes, just long enough for the chicken to heat through.

5. Remove the soup from the heat. Stir in the fresh chopped parsley. Taste the soup and season generously with salt and black pepper as needed. Remember, the amount of salt will depend on your broth and personal preference.

6. Ladle the hot soup into bowls and serve immediately. A little extra fresh parsley or a lemon wedge for squeezing can be a nice touch.